Because there is a reflection from the sun hits the moon the moon reflects the light on earth
The correct answer is A. Between the visceral and parietal layers of serous membranes
Explanation:
Serous fluid is a type of pale yellow fluid similar to mucus that is secreted by certain membranes to reduce friction in body cavities. This can be found on different organs in the body including the digestive system, for example in the peritoneum that encloses multiple organs in the abdomen. Additionally, serious fluid develops between two main layers: the visceral layer that covers the organs and the parietal layer that follows the visceral layer. According to this, serous fluid reduces friction "between the visceral and parietal layers of serous membranes".
The main responsible for the delay among the atrial and
ventricular contractions is the action potential conduction velocity of the AV
node cells. If the atria and ventricles contract simultaneously, atria cannot
give any help in filling the ventricles, which is needed, especially in those
with stiff ventricles as in the elderly. Hence atria have to contract first and
then the ventricles.